8255936: "parsing found no loops but there are some" assertion failure with Shenandoah

Reviewed-by: thartmann, rkennke

Author: rwestrel

src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp

@@ -49,7 +49,7 @@ bool ShenandoahBarrierC2Support::expand(Compile* C, PhaseIterGVN& igvn) {
        state->load_reference_barriers_count()) > 0) {
     bool attempt_more_loopopts = ShenandoahLoopOptsAfterExpansion;
     C->clear_major_progress();
-    PhaseIdealLoop ideal_loop(igvn, LoopOptsShenandoahExpand);
+    PhaseIdealLoop::optimize(igvn, LoopOptsShenandoahExpand);
     if (C->failing()) return false;
     PhaseIdealLoop::verify(igvn);
     DEBUG_ONLY(verify_raw_mem(C->root());)

test/hotspot/jtreg/gc/shenandoah/compiler/BarrierInInfiniteLoop.java

@@ -30,6 +30,8 @@
  *
  * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -Xcomp -XX:CompileOnly=BarrierInInfiniteLoop::test1
  *                   -XX:CompileOnly=BarrierInInfiniteLoop::test2 -XX:CompileOnly=BarrierInInfiniteLoop::test3 -XX:CompileCommand=quiet BarrierInInfiniteLoop
+ * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCMode=iu -Xcomp -XX:CompileOnly=BarrierInInfiniteLoop::test1
+ *                   -XX:CompileOnly=BarrierInInfiniteLoop::test2 -XX:CompileOnly=BarrierInInfiniteLoop::test3 -XX:CompileCommand=quiet BarrierInInfiniteLoop
  *
  */